TW: friendship problems

Hi, I'm not really sure why I'm posting this, I guess I just wanted other perspectives. I am struggling alot with being really scared of seeing a friend that I work with (well perhaps an ex-friend now). 

She's really been there for me the past six months when things have been very difficult (without going into detail, I've had an ex border on stalking and it resulted in an assault, gifts sent to work, home etc, it's been complex. It is being handled by police and thankfully he's being held now.) This friend at work has been so supportive and kind, but something has changed recently, I feel like she is pulling away alot and I'm not sure why. She hasn't said anything but she's stopped responding, barely speaks to me and just seems different, she's brushed off when I've tried to start a conversation. 

I was expecting it to come and I don't blame her, there's been something happen almost weekly for months, none of which I've been able to control. Whether it's parcels, messages etc, all been reported and I've followed all the advice I've been given by authorities and am in therapy. But I was expecting it to become too much for her, she doesn't owe me anything and I appreciate how supportive she has been to now. I just wish I could change it. I know she could be dealing with something and need distance, I just wish she'd say if that was the case because at the moment I just feel bad for becoming too much and perhaps too emotional around her at times. 

I guess I'm just really heartbroken, she was one of the few people that I could feel secure around and safe to open up to and I've worked hard to be positive or at least neutral so I don't bring the mood down all the time. It's just awful and devastating to lose her, and now I don't know how to be at work with her. I considered giving her a letter but know that's cringe and awkward, the thought of seeing her now just makes me want to cry. I don't know what I'm looking for, just some advice I guess on what to do next, I'll be going to work in about 8 hours and just don't know how to be.